This invention relates to liquid ring pumps, and more particularly to liquid ring pumps with two, serially connected, gas pumping stages.
Two-stage liquid ring pumps are well known, as is shown, for example, by Olsen et al. U.S. Pat. No. 4,521,161. In the usual such pump, a mixture of gas and liquid is discharged from the first stage and passed to the inlet of the second stage. The liquid in this mixture is generally needed in the second stage (e.g., to make up for liquid discharged with the gas from the second stage). However, it is believed that the liquid in the mixture coming from the first stage may to some extent choke the second stage inlet, thereby reducing the pressure differential that the pump can achieve, reducing its volumetric capacity, and/or increasing its power requirements.
In view of the foregoing, it is an object of this invention to provide improved two-stage liquid ring pumps.
It is a more particular object of this invention to increase the pressure range and volumetric capacity and to reduce the power requirements of two-stage liquid ring pumps.